Recently, digital still cameras and digital video cameras equipped with image sensors such as charge-coupled device (CCD) and complementary metal-oxide-semiconductor (CMOS) sensors have become prevalent. A digital still camera captures still images while a digital video camera captures moving images, but there also exist digital still cameras capable of capturing moving images and digital video cameras capable of capturing still images. Note that in the following, digital still cameras and digital video cameras may simply be designated a “digital camera” when not being particularly distinguished. Also, in the following, still images and moving images may simply be designated an “image” when not being particularly distinguished.
In many cases, a digital camera as above includes a function of an autofocus process that performs focusing automatically, as disclosed in Patent Literature 1. In an autofocus process, the distance between the digital camera and the subject is measured, and the lens is driven on the basis of the measured distance to suitably adjust the focus, for example. As a result, acquiring an in-focus (focused) image becomes possible.